20以内是合数又是质数的有哪些答:合数 : 4,6,8,9,10,12,14,15,16,18,20 质数 : 2,3,5,7,11,13,17,19
百数表中哪些是合数?答:1~100的自然数中,合数共有74个:4, 6, 8, 9, 10, 12, 14, 15, 16, 18, 20, 21, 22, 24, 25, 26, 27, 28, 30, 32, 33,34, 35, 36, 38, 39, 40, 42, 44, 45, 46, 48, 49, 50, 51, 52, 54, 55, 56, 57, 58,60, 62, 63, 64, 65, 66, 68, 69, ...